Structural glue-jointed wood products, such as dimensional lumber, is gaining greater acceptance for a wide variety of applications in the building and construction industry. Recognition that efficient utilization of wood resources will continue to be necessary, that reduction of flow to local land fills is a priority in many locations, and cost and reliability factors have continued to fuel the desire to make more of such jointed product available.
However, current finger-jointing technology has not changed substantially to keep pace with the demand. Scarf joints and finger joints of various types have long been utilized, improvements lying primarily in the field of new adhesives and/or adhesive application techniques. While many are acceptable for some applications, few if any of the known joints have proved effective for application under all significant loading conditions (tension, compression, bending, torsion and shear).
Moreover, greater efficiencies and ease of manufacture could still be utilized. Scarf joints, for example, require large amounts of wood removal for joint construction. Most current finger joint production requires provision of large-scale (and, thus, centralized) production facilities, thereby necessitating shipment of scrap lumber to the facility, often from great distances. Specialized handling of jointed materials due to fragility of the freshly glued joints is also often required. The shipping requirement increases cost and energy consumption for production, and deters many non-local companies from use of this alternative, while the special handling requirements increase cost and space requisites (production and storage) of such facilities. In addition to the high cost of industrial finger jointing equipment, smaller scale operations are thus discouraged.
Additionally, traditional facilities are not able to process post-consumer, possibly contaminated, lumber because the blades necessary for production of known joints are at risk of damage by foreign materials commonly found in post-construction scrap, demolition scrap, and the like. A finger joint construction modeled for use of such post-consumer scrap would, if accepted, greatly reduce the volume of land filled construction and demolition waste.